• YAKHAK HOEJI
• /
• v.41 no.6
• /
• pp.829-836
• /
• 1997

Studies on the effect of quinones on cardiac function has been conducted with normal hearts. But not with injured hearts, I.e. ischemia/reperfusion-injured heart. Quinone compounds are known to produce oxygen free radicals during metabolism, and for this reason, quinones are implicated in the aggravation of ischemia/reperfusion injury or cardioprotection, as in the case of ischemic preconditioning depending on the experimental conditions. The present study was carried out to examine the effect of 2-chloro-3-(4-cyanophenylamino)-1.4-naphthoquinone (NQ-Y15) on cardiac function of ischemic/reperfused and normal rat hearts. In isolated perfused hearts, various functional parameters such as left ventricular developed pressure (LVDP), left ventricular end-diastolic pressure (EDP) and maximum positive and negative dP/dt ($[\pm}dP/dt_{max}$), time to contracture, heart rate (HR) and coronary flow rate (CFR) were measured before and 30 min after dosing and following 25 min ischemia/30min reperfusion. NQ-Y15 increased LVDP, +dP/$d_{max}$and -dP/$dt_{min}$ by 18%. 30%, and 40%, respectively. There were no significant changes in other haemodynamic parameters. After ischemia/reperfusion injury, pretreatment with NQ-Y15 induced a significant decrease in LVDP and $[\pm}dP/dt_{max}$, but an increase in EDP. LDH-release was not significantly increased. These results suggested that NQ-Y15 may augment the ventricular contractility but it makes hearts more vulnerable to ischemia/reperfusion injury.

• Environmental Analysis Health and Toxicology
• /
• v.12 no.3_4
• /
• pp.75-84
• /
• 1997

Chromatographic retention behavior and separation of various phenol derivatives on a Partisil 10 ODS 3 column-with mobile phase containing $\alpha$-cyclodextrin-were systematically studied. The decrease in k' values caused by the addition of cyclodextrins in the mobile phase was based on the formation of an inclusion complex, resulting in weakening of the hydrophobic interaction between solutes and the stationary phase. The content of the organic solvent in the mobile phase also influenced k' values of the solutes, and k' values increased with a decrease of the content of organic solvent in the mobile phase. A simple equation has been derived that reveals the hyperbolic dependence of the capacity factor on the total concentration of cyclodextrin. A plot of the reciprocal of the capacity factor against (CD)$_T$ gives a straight line and the dissociation constant, K$_D$, of the inclusion complex can be calculated from the slope. The capacity factor decreased with increasing temperature. The enthalpy was calculated from the slope of van't Hoff plots. Under optimum conditions, some mixtures of phenol derivatives were able to separated successfully.

• YAKHAK HOEJI
• /
• v.37 no.3
• /
• pp.216-227
• /
• 1993

Complex formations of practically insoluble antelmintic drugs such as mebendazole (MBZ), albendazole (ABZ) and flubendazole (FBZ) with dimethyl-$\beta$-cyclodextrin (DM-$\beta$-CyD) and 2-hydroxypropyl-$\beta$-cyclodextrin (HP-$\beta$-CyD) together with $\alpha$-, $\beta$- and $\gamma$-cyclodextrins(CyDs) in duffered solutions were investigated by solubility method. $A_{L}$ type phase solubility diagrams were obtained in all cases except for the complexation (B$_{s}$, type) of FBZ with $\gamma$-CyD. The highest stability constants were obtained with DM-$\beta$-CyD, followed by $\alpha$-CyD > $\beta$-CyD > HP-$\beta$-CyD > $\gamma$-CyD for ABZ, and HP-$\beta$-CyD > $\gamma$-CyD > $\beta$-CyD > $\alpha$-CyD for FBZ at pH 1.2. On the other hand, solid dispersion systems of ABZ and FBZ with $\beta$- and DM-$\beta$-CyDs were prepared by solvent evaporation method and evaluated by dissolution, differential thermal analysis and powder x-ray diffractometry. The dissolution rates of ABZ- and FBZ-DM-$\beta$-CyD solid dispersions were much faster than those of drugs alone, corresponding physical mixtures and tablets on market both at pH 1.2 and 6.8. Although dissolution rates of all samples at pH 6.8 were by far lower than those obtained at pH 1.2, as explained by pH-solubility profiles for ABZ and FBZ, the dissolution rates at pH 6.8 of ABZ from $\beta$- and DM-$\beta$-CyD solid dispersions exceeded the respective equilibrium solubility (23.9 $\mu\textrm{g}$/ml). Fast dissolution of ABZ from solid dispersions with CyDs was attributed to the reduction of drug crystallinity and particle size which was supported by DTA and powder x-ray diffractometry. Consequently these results suggest that solid dispersion systems with CyDs may provide useful means to markedly enhance the solubility and dissolution of benzimidazole antelmintic drugs.

• Restorative Dentistry and Endodontics
• /
• v.29 no.6
• /
• pp.548-552
• /
• 2004

Intracanal disinfection of infected root canal is one of important treatment procedure. This in vitro study aimed to evaluate whether the surface polymers of controlled release drug (CRD) can effectively control the release rate of chlorhexidine for root canal disinfection. Four CRD prototypes were prepared: Group A (n=12); The core device (absorbent paper point) was loaded with 40% CHX solution as control. Group B (n=12); same as group A, but the device was coated with chitosan. Group C (n=12); same as group A and then coated three times with 5% PMMA. Group D (n=12); same as group A and then coated three times with 3% PLGA. All CRD prototypes were soaked in 3 mL distilled water for experimental periods and the concentrations of released CHX from each CRD prototype were determined using a UV spectrophotometer. Results showed that release rate of CHX were the greatest in the non-coated group (control group), followed by the chitosan-coated group, the PLGA-coated group, and the PMMA-coated group (P < 0.05). This data indicate that surface polymers can control the release rate of CHX from the CRD prototypes.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.22 no.3
• /
• pp.8-13
• /
• 2018

Zirconium potassium perchlorate(ZPP) is an igniter composed of potassium perchlorate as an oxidizing agent and zirconium as a fuel with a Viton binder. ZPP has been used to provide an ignition source in the aerospace, propulsion, and automotive industries. This study investigates the manufacturing process and characteristics of ZPP, such performance and shape/calorimetry/pressure characteristics with respect to pyrotechnic mechanical device(PMD). During the production of ZPP, the mixing process was designed to produce uniform particle size and shape by mixing the raw materials at high speed.

• Geophysics and Geophysical Exploration
• /
• v.16 no.3
• /
• pp.154-162
• /
• 2013

Vertical electrical sounding and 2D electrical resistivity survey were applied for evaluating the characteristics of alluvial layers at a groundwater artificial recharge site. The fine particles in alluvial layer, main target layer of groundwater artificial recharge, may cause clogging phenomena. In this case, electrical resistivity method is an effective technique to verify the spatial distribution of low-resistivity layers, such as saturated silts and clays. On the other hand, much attention should be paid to interpret the resistivity data in unconsolidated layers, because thick clayey overburden sometimes produces a masking effect on underlying interbedded resistive sands and gravels. Considering these points, we designed 35 points arranged in a grid form for vertical electrical sounding and 10 lines for 2D electrical resistivity survey, and concentrated our effort on enhancing the vertical and horizontal resolution of resistivity images. According to the results, 15 meters thick layers consisting of sands and gravels are located in 30 meters below ground. And the spatial distribution of silts and clays are mapped, which may cause clogging. Consequently, this approach can contribute to design and determine the location and depth of injection and observation wells for groundwater artificial recharge.

• Korean Journal of Biological Psychiatry
• /
• v.13 no.3
• /
• pp.152-161
• /
• 2006

Objective : The relationship between the total daily dose of clozapine given and the plasma concentrations of clozapine and its metabolites(N-desmethylclozapine and clozapine N-oxide) and the effect of Glu158Lys (wild-type : Glu, 'H' ; variant : Lys, 'h') and Glu308Gly(wild-type : Glu, 'D' ; variant : Lys, 'd') variation in FMO3 gene on plasma concentrations of clozapine and its metabolites was studied in schizophrenic patients. Methods : Trough plasma concentrations of clozapine and its metabolites were measured in 34 schizophrenic patients receiving clozapine. The genetic variation of 'h' and 'd' in FMO3 were analyzed in 21 among 34 patients. Results : A linear relationship between the total daily dose of clozapine given(mg/kg body weight per day) and the plasma concentrations(nM) of clozapine was revealed by regression analysis(p<0.001) in the 23 patients receiving a constant daily dose of clozapine for 8 days. The plasma molar concentration ratios of clozapine N-oxide/clozapine in 8 subjects with 'hh' or 'Hh' alleles were not different from those in 6 subjects with 'HH' alleles and the plasma molar concentration ratios in 6 subjects with 'dd' or 'Dd' alleles were not different from those in 8 subjects with 'DD' alleles. Conclusion : The effect of Glu158Lys and Glu308Gly variation in FMO3 gene on clozapine metabolism could not be shown.

• Korean Journal of Medicinal Crop Science
• /
• v.7 no.2
• /
• pp.143-146
• /
• 1999

The cytotoxicity-guided fractionation of the seed of Plantago asiatica extracts led to the isolation of four compounds, responsible for the cytotoxicity against four human tumor cell lines, i. e., A431 (Human Epidermoid carcinoma), KHOS-NP (Human Osteosarcoma). SNU-1 (Human stomach carcinoma), SNU-C4 (Human large intestine carcinoma). The structure were elucidated by the phsyco chemical data: ${\beta}-sitosterol(C1)$, $cholest-5-en-3{\beta}-ol(C2)$, rutin(C3), $coumarin-7-O-{\beta}-glucopyranoside(C4)$. $IC_{50}$ values of compound C2 were 14.6, 13.5, 10.3, 17.8 ${\mu}g/ml$, and compound C3 and C4 showed activity, having $IC_{50}$ values ranging from 10.3 to 20.14 ${\mu}g/ml$.

• The Journal of the Petrological Society of Korea
• /
• v.7 no.3
• /
• pp.190-206
• /
• 1998

The microstructures and time-relationship between deformation and growth of metamorphic minerals(metamorphism) of the Paleozoic metasedimentary rocks(Joseon Supergroup and Pyeongan Group) in the Janggunbong area at the central-south part in the North Sobaegsan Massif, Korea, have been analyzed in this paper. The first phase metamorphism (low-pressure type metamorphism), recognized as the crystallization of stack-type chloritoid and biotite and augen-type old andalusite, occurred under non-deformational condition before D1 deformation related to the formation of an E-W trending isocline-synclinal fold(Janggunbong fold) and associated its axial plane S1 foliation, and produced regional mineralogical zoning of E-W trend in the Paleozoic rocks. The second phase metamorphism(medium-pressure type metamorphism), related to the growth of staurolite and garnet porphyroblasts with straight or curved internal foliations(Si), occurred under non-deformational condition after D1 deformation related to the formation of E-W trending thrusts modifying the Janggunbong fold and during D2 deformation related to the formation of E-W trending Yecheon shear zone. This metamorphism also produced regional mineralogical zoning of E-W trend. After D2 deformation occurred the intrusion of Jurassic Chunyang granite and associated its contact metamorphism which crystallized patchy-type young andalusite and prismatic- or fibrous-type sillimanite and coarse-grained garnet. This metamorphism occurred under non-deformational condition before D3 deformation related to the formation of S3 crenulation cleavage and during early phase of D3 deformation, and formed narrow mineralogical zoning of N-S trend near Chunyang granite.

• YAKHAK HOEJI
• /
• v.38 no.3
• /
• pp.300-310
• /
• 1994

Physicochemical properties for the inclusion complex of chenodeoxycholic acid(CDCA) and it's $7{\beta}-hydroxy$ epimer ursodeoxycholic acid(UDCA) with ${\beta}-cyclodextrin({\beta}-CyD)$ were studied. The formation of the complex in the solid state were confimed by polarized microscopy and differential scanning calorimetry(DSC). Proton nuclear magnetic resonance$(^1H-NMR)$spectroscopy showed that CDCA and UDCA form an inclusion complex with ${\beta}-CyD$ in aqueous solution. The 1 : 1 stoichiometry of the complex was dextermined by the continuous variation method. From DSC and $^1H-NMR$ studies, there were not any differences between CDCA and UDCA. Complex of CDCA and UDCA showed increase in solubility and dissolution compared with CDCA and UDCA alone, respectively. Solubility pattern of UDCA complex was pH independent but, CDCA complex was like that of CDCA. Dissolution rate increased markedly in case of UDCA complex compared with CDCA complex, especially in acidic pH value.